hw/block/block.c

   1 /*
   2  * Common code for block device models
   3  *
   4  * Copyright (C) 2012 Red Hat, Inc.
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or
   7  * later.  See the COPYING file in the top-level directory.
   8  */
   9
  10 #include "qemu/osdep.h"
  11 #include "sysemu/blockdev.h"
  12 #include "sysemu/block-backend.h"
  13 #include "hw/block/block.h"
  14 #include "qapi/error.h"
  15 #include "qapi/qapi-types-block.h"
  16
  17 /*
  18  * Read the entire contents of @blk into @buf.
  19  * @blk's contents must be @size bytes, and @size must be at most
  20  * BDRV_REQUEST_MAX_BYTES.
  21  * On success, return true.
  22  * On failure, store an error through @errp and return false.
  23  * Note that the error messages do not identify the block backend.
  24  * TODO Since callers don't either, this can result in confusing
  25  * errors.
  26  * This function not intended for actual block devices, which read on
  27  * demand.  It's for things like memory devices that (ab)use a block
  28  * backend to provide persistence.
  29  */
  30 bool blk_check_size_and_read_all(BlockBackend *blk, void *buf, hwaddr size,
  31                                  Error **errp)
  32 {
  33     int64_t blk_len;
  34     int ret;
  35
  36     blk_len = blk_getlength(blk);
  37     if (blk_len < 0) {
  38         error_setg_errno(errp, -blk_len,
  39                          "can't get size of block backend");
  40         return false;
  41     }
  42     if (blk_len != size) {
  43         error_setg(errp, "device requires %" HWADDR_PRIu " bytes, "
  44                    "block backend provides %" PRIu64 " bytes",
  45                    size, blk_len);
  46         return false;
  47     }
  48
  49     /*
  50      * We could loop for @size > BDRV_REQUEST_MAX_BYTES, but if we
  51      * ever get to the point we want to read *gigabytes* here, we
  52      * should probably rework the device to be more like an actual
  53      * block device and read only on demand.
  54      */
  55     assert(size <= BDRV_REQUEST_MAX_BYTES);
  56     ret = blk_pread(blk, 0, buf, size);
  57     if (ret < 0) {
  58         error_setg_errno(errp, -ret, "can't read block backend");
  59         return false;
  60     }
  61     return true;
  62 }
  63
  64 void blkconf_blocksizes(BlockConf *conf)
  65 {
  66     BlockBackend *blk = conf->blk;
  67     BlockSizes blocksizes;
  68     int backend_ret;
  69
  70     backend_ret = blk_probe_blocksizes(blk, &blocksizes);
  71     /* fill in detected values if they are not defined via qemu command line */
  72     if (!conf->physical_block_size) {
  73         if (!backend_ret) {
  74            conf->physical_block_size = blocksizes.phys;
  75         } else {
  76             conf->physical_block_size = BDRV_SECTOR_SIZE;
  77         }
  78     }
  79     if (!conf->logical_block_size) {
  80         if (!backend_ret) {
  81             conf->logical_block_size = blocksizes.log;
  82         } else {
  83             conf->logical_block_size = BDRV_SECTOR_SIZE;
  84         }
  85     }
  86 }
  87
  88 bool blkconf_apply_backend_options(BlockConf *conf, bool readonly,
  89                                    bool resizable, Error **errp)
  90 {
  91     BlockBackend *blk = conf->blk;
  92     BlockdevOnError rerror, werror;
  93     uint64_t perm, shared_perm;
  94     bool wce;
  95     int ret;
  96
  97     perm = BLK_PERM_CONSISTENT_READ;
  98     if (!readonly) {
  99         perm |= BLK_PERM_WRITE;
 100     }
 101
 102     shared_perm = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
 103                   BLK_PERM_GRAPH_MOD;
 104     if (resizable) {
 105         shared_perm |= BLK_PERM_RESIZE;
 106     }
 107     if (conf->share_rw) {
 108         shared_perm |= BLK_PERM_WRITE;
 109     }
 110
 111     ret = blk_set_perm(blk, perm, shared_perm, errp);
 112     if (ret < 0) {
 113         return false;
 114     }
 115
 116     switch (conf->wce) {
 117     case ON_OFF_AUTO_ON:    wce = true; break;
 118     case ON_OFF_AUTO_OFF:   wce = false; break;
 119     case ON_OFF_AUTO_AUTO:  wce = blk_enable_write_cache(blk); break;
 120     default:
 121         abort();
 122     }
 123
 124     rerror = conf->rerror;
 125     if (rerror == BLOCKDEV_ON_ERROR_AUTO) {
 126         rerror = blk_get_on_error(blk, true);
 127     }
 128
 129     werror = conf->werror;
 130     if (werror == BLOCKDEV_ON_ERROR_AUTO) {
 131         werror = blk_get_on_error(blk, false);
 132     }
 133
 134     blk_set_enable_write_cache(blk, wce);
 135     blk_set_on_error(blk, rerror, werror);
 136
 137     return true;
 138 }
 139
 140 bool blkconf_geometry(BlockConf *conf, int *ptrans,
 141                       unsigned cyls_max, unsigned heads_max, unsigned secs_max,
 142                       Error **errp)
 143 {
 144     if (!conf->cyls && !conf->heads && !conf->secs) {
 145         hd_geometry_guess(conf->blk,
 146                           &conf->cyls, &conf->heads, &conf->secs,
 147                           ptrans);
 148     } else if (ptrans && *ptrans == BIOS_ATA_TRANSLATION_AUTO) {
 149         *ptrans = hd_bios_chs_auto_trans(conf->cyls, conf->heads, conf->secs);
 150     }
 151     if (conf->cyls || conf->heads || conf->secs) {
 152         if (conf->cyls < 1 || conf->cyls > cyls_max) {
 153             error_setg(errp, "cyls must be between 1 and %u", cyls_max);
 154             return false;
 155         }
 156         if (conf->heads < 1 || conf->heads > heads_max) {
 157             error_setg(errp, "heads must be between 1 and %u", heads_max);
 158             return false;
 159         }
 160         if (conf->secs < 1 || conf->secs > secs_max) {
 161             error_setg(errp, "secs must be between 1 and %u", secs_max);
 162             return false;
 163         }
 164     }
 165     return true;
 166 }